Disinfection Online Part 1 RECORDED

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Instructors: Greg & Patresha Pearson, RN; CSUS-OWP Instructors COPYRIGHT 2011 GREPA Health & Environmental – All rights reserved:

Instructors : Greg & Patresha Pearson, RN; CSUS-OWP Instructors COPYRIGHT 2011 GREPA Health & Environmental – All rights reserved Introduction To Disinfection Dosing & Water Quality Relationships  Welcomes You!

Slide 2:

Source Coagulation Flocculation Sedimentation Filtration Disinfection Source to Tap Module By Patresha Pearson, RN Graphics by Greg Pearson

Slide 3:

Copyright 2007 Patresha Pearson RN Al rights reserved

Water Personality:

Water Personality Water has attitudes with characteristics that acts like a person, having likes, dislikes and certain demonstrated characteristics that manifest themselves through sources and quality outcomes: Agree? Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Characteristics of water:

Characteristics of water Water is a composite , chemical substance formed with one (O 2 ) oxygen atom, married to two (2H 2 ) Hydrogen atoms forming a covalent bond. Water is in a class by itself: How so? It is the only substance that exists in 3 states in nature. Liquid Solid Gaseous Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Water Sources:

Water Sources Ground Water Surface Water Seawater Rainwater Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Water Quality:

Water Quality General term used to describe the physica l, chemical , and biological characteristics of a water supply: A potable domestic water source is said to be of good quality when it is free of toxic chemicals, disease causing microorganisms, and unpleasant tastes and odors. Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Contaminants:

Contaminants Copyright 2007 Patresha Pearson RN Al rights reserved Agents/Source Chemical Microbiological

Water Quality Standards:

Water Quality Standards Primary Secondary Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Health - Arsenic - Mercury - Chromium - Lead - Aesthetics - Taste - Odor - Color - Hardness

Water Quality Characteristics:

Water Quality Characteristics Groundwater Surface Water Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Minerals Hardness Natural filtration Protected GWR applies Organics Pathogens Easy to pollute Soft – low minerals SWTR applies

Disinfection :

Disinfection What is the ultimate goal of proper disinfection? P revent waterborne disease; it is easier to prevent than to treat water borne illnesses. Implementation Includes Removal and or Inactivation of pathogens P roduce a measurable chlorine residual Provide sufficient contact time Safety precautions Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorine Chemical :

Chlorine Chemical Chlorine chemical is widely used in the conventional treatment processes as a disinfectant, algaecide, and oxidizer. Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

When Is Disinfection Necessary?:

When Is Disinfection Necessary? When protecting finished water in a distribution system from contamination or bacterial growths When treating surface water or ground water under the influence When any repairs or additions are done to the DS When contaminants may have entered the system through backflow, main breaks , new line installation, improper screening or flooding, cross-connections. Well water may also require disinfection Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Disinfection/Treatment Process :

Disinfection/Treatment Process Pre-chlorination: The initial dosing of chlorine in raw water before the filtration plant, kills most disease-causing micro-organisms and may help to control taste and odor causing substances, algal growths, and slimes: Post- Chlorination : Occurs after filtration of suspended solids: when chlorine is added at this time it produces a residual in the distribution system, and has less potential for forming D B P at this time. Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Water Quality Conditions :

Water Quality Conditions Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Source Water Seasonal changes. Increasing/Decreasing temperature. Decrease in water use . Detention time Disinfection Byproducts

Methods of Disinfection:

Methods of Disinfection Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Physical methods Ultraviolet rays Heat Ultrasonic waves Chemical methods Iodine Bromine Bases Chloramines Ozone Chlorine

Ozone – O3:

Ozone – O3 Ozone gas is generated by passing oxygen (O2) through electricity allowing the O2 which splits, reattaches forms a new molecule and become O3 Very effective disinfectant, not proven to be carcinogenic (if no bromide exists) Equipment can be expensive Electrical costs can be high Must be generated on site Residual does not last long Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Slide 18:

Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Ozone gas is generated by passing oxygen (O2) through electricity allowing the O2 to split, reattach and become O3 Oxygen is exposed to high voltage discharge. The oxygen molecules split & reattach to become O 3 Venturi mixes O 3 and water Residual lasts about 30 min.

Ozone :

Ozone Advantages: Most effective against cryptosporidium Oocyst Less likely to produce DBP Disadvantages of using Ozone: Must be generated onsite Does not leave a residual in treated water Very corrosive Containers must be Stainless Steel due to ozone corrosivity Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Known Facts about Chlorine:

Known Facts about Chlorine Discovered in 1774 Recognized as a chemical agent in1810 First used in 1854 London to stop a deadly cholera outbreak. First used as a disinfectant in the US in 1907 Now used in hundreds of applications from cell phones, to PVC plastic Has contributed more to human health than any other technology Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Coliform Bacteria:

Coliform Bacteria Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Indicator organism that alerts operators there may be a potential organism invasion in your water system. Further testing needs to be performed to determine the nature and type of coliform present in the water.

Coliform:

Coliform This group of bacteria include both pathogenic and non-pathogen species, found in the intestines of warm blooded animals. Rod shaped bacteria that ferments lactose in a media at 35 o C Indicator organism: Always present in fecal contamination More persistent than pathogenic bacteria Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Coliform sampling:

Coliform sampling Required monthly testing Within 24 hours after a positive sample result At the representative point and throughout the distribution system Number of samples taken is based on the population served Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Testing Methods:

Testing Methods Colisure Readycult and Colitag Most media is geared to inhibit the growth of certain kinds of bacteria and encourage the growth of others. A Media is used to differentiate between coliform, Eoli and fecal coliform This is called selective testing method MNO-MUG - a clear compound with lactose fermenting bacteria Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Heterotrophs:

Heterotrophs Heterotrophic groups of bacteria uses organic nutrients as a source of carbon manufacturing to grow more rapidly than most species of bacteria in the presence of Nitrifying bacteria. An Increase in heterotrophic bacteria could be an indication of occurring nitrification bacteria in your reservoir or distribution system Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

HTPC :

HTPC Heterotrophic plate count is a testing method used to enumerate bacterial growth count in water samples A drop of water is placed in a petri dish with various nutrients & left for about 48 hours in a warm environment. After 48 hours the total number of colonies formed indicate the number and species of bacteria growing in a water sample Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute Coliform groups

Common Water Borne Diseases:

Common Water Borne Diseases Typhoid Fever Cholera Hepatitis E. coli Salmonella Shigella Legionella Giardia Cryptosporidium Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorination Action:

Chlorination Action How does chlorine kill microorganisms? Bacteria : Penetrates cell wall and kills the organism Viruses : Inactivation (incapable of reproduction) Giardia : Inactivation Cryptosporidium : Used alone, chlorine has no disinfecting effect on this protozoan microorganism Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Cryptosporidium Oocyst:

Cryptosporidium Oocyst Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Cryptosporidium & Enhanced SWTR:

Cryptosporidium & Enhanced SWTR SWTR Rule: Compulsory Filtration disinfection for surface water Turbidity (cloudiness) must be measured before and after treatment processes Mandatory 4 log removal with fecal coliform results 99.99 % indicates the number of log removal Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorination Process:

Chlorination Process C haracteristics affecting the disinfection process? High pH Low water temperature Turbidity Hardness Presence of chlorine-demanding compounds (e.g . iron, manganese ) Nitrogen fixing bacteria– these bacteria are very resistant to Chloramines The byproduct of nitrifying bacteria may support coliform bacterial growth in your reservoir, storage tanks or distribution system Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Turbidity:

Turbidity Finely divided particles of sand silt clay and organics form c loudiness in water: Shields disease causing microorganisms eg crypto Decreases or blocks the effectiveness of disinfecting chemicals such as chlorine Turbidity is measured in NTU Normal measurement is under .1 NTU Reference: The Milwaukee incident: 1993 Crypto outbreak causing massive loss of lives Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

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Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Reducing Compounds :

Reducing Compounds

Chlorine Dosing Considerations:

Chlorine Dosing Considerations Demand + Residual = Dose Demand : amount needed to kill or inactivate pathogens and react with reducing agents- this must be satisfied to end up with a residual Residual – amount of free or combined chlorine after initial kill Dose – the amount of chlorine needed to meet demand and residual Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

reaching Breakpoint – :

Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute reaching Breakpoint – By Adding Chlorine Until Demand Is satisfied

Chloramines :

Chloramines Compounds formed by the reaction of Hypochlorous acid with ammonia (NH3) Can occur as a byproduct of disinfection as a result of contact with nitrogen and ammonia compound in water Chloramines can be used purposely as a disinfection Advantages of using Chloramines as a disinfectant Reduces THM and DBP Reduces taste and odor problems Residual lasts longer than chlorine Not effective against nitrifying bacteria Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Chlorine Dioxide :

Chlorine Dioxide Must be generated onsite Very effective form of disinfection Less likely to produce DBP Used in the paper manufacturing industry Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Forms of Disinfection Byproducts :

Forms of Disinfection Byproducts TTHM – totaltrihalomethanes are carcinogenic substances formed from the reaction of chlorine and organic compounds HAA5 – Haloacetic acid is another form of DBP Chloramines and Chlorine Dioxide are two forms of chlorine which do not produce disinfectant byproducts Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

Slide 40:

Coming Up Next! Chorine Types Disinfection Methods Dosage Math See you there! Copyright 2010 GRepa Health & Environmental - Do not recopy or redistribute

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